I don't think it's a secret that there are many people out there who don't believe there is a God or that Jesus is the Son of God and can forgive us of our sins, etc. Well, people didn't believe it when Jesus walked the earth Himself, but here was His answer to the nay-sayers.
John 10:36b-38 ~ I am the one God chose and sent into the world. If I don’t do what my Father does, then don’t believe Me. But if I do what My Father does, even though you don’t believe in Me, believe what I do. Then you will know and understand that the Father is in Me and I am in the Father.” (NCV)
Even if people don't believe in what you believe, let them believe in what you do. Give them something to believe in. Faith should be visible in your life, let it be. Act in a way so you give people something to believe in, you may be surprised at how it works.